Substructure depletion in the Milky Way halo by the disk

Understand

We employ numerical simulations and simple analytical estimates to argue that dark matter substructures orbiting in the inner regions of the Galaxy can be efficiently destroyed by disk shocking, a dynamical process known to affect globular star clusters.

• We carry out a set of fiducial high-resolution collisionless simulations in which we adiabatically grow a disk, allowing us to examine the impact of the disk on the substructure abundance.
• We also track the orbits of dark matter satellites in the high-resolution Aquarius simulations and analytically estimate the cumulative halo and disk shocking effect.
• Our calculations indicate that the presence of a disk with only 10% of the total Milky Way mass can significantly alter the mass function of substructures in the inner parts of halos.